GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / firmware / raspberrypi.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Defines interfaces for interacting with the Raspberry Pi firmware's
4  * property channel.
5  *
6  * Copyright © 2015 Broadcom
7  */
8
9 #include <linux/dma-mapping.h>
10 #include <linux/kref.h>
11 #include <linux/mailbox_client.h>
12 #include <linux/module.h>
13 #include <linux/of_platform.h>
14 #include <linux/platform_device.h>
15 #include <linux/slab.h>
16 #include <soc/bcm2835/raspberrypi-firmware.h>
17
18 #define MBOX_MSG(chan, data28)          (((data28) & ~0xf) | ((chan) & 0xf))
19 #define MBOX_CHAN(msg)                  ((msg) & 0xf)
20 #define MBOX_DATA28(msg)                ((msg) & ~0xf)
21 #define MBOX_CHAN_PROPERTY              8
22
23 static struct platform_device *rpi_hwmon;
24 static struct platform_device *rpi_clk;
25
26 struct rpi_firmware {
27         struct mbox_client cl;
28         struct mbox_chan *chan; /* The property channel. */
29         struct completion c;
30         u32 enabled;
31
32         struct kref consumers;
33 };
34
35 static DEFINE_MUTEX(transaction_lock);
36
37 static void response_callback(struct mbox_client *cl, void *msg)
38 {
39         struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
40         complete(&fw->c);
41 }
42
43 /*
44  * Sends a request to the firmware through the BCM2835 mailbox driver,
45  * and synchronously waits for the reply.
46  */
47 static int
48 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
49 {
50         u32 message = MBOX_MSG(chan, data);
51         int ret;
52
53         WARN_ON(data & 0xf);
54
55         mutex_lock(&transaction_lock);
56         reinit_completion(&fw->c);
57         ret = mbox_send_message(fw->chan, &message);
58         if (ret >= 0) {
59                 if (wait_for_completion_timeout(&fw->c, HZ)) {
60                         ret = 0;
61                 } else {
62                         ret = -ETIMEDOUT;
63                         WARN_ONCE(1, "Firmware transaction timeout");
64                 }
65         } else {
66                 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
67         }
68         mutex_unlock(&transaction_lock);
69
70         return ret;
71 }
72
73 /**
74  * rpi_firmware_property_list - Submit firmware property list
75  * @fw:         Pointer to firmware structure from rpi_firmware_get().
76  * @data:       Buffer holding tags.
77  * @tag_size:   Size of tags buffer.
78  *
79  * Submits a set of concatenated tags to the VPU firmware through the
80  * mailbox property interface.
81  *
82  * The buffer header and the ending tag are added by this function and
83  * don't need to be supplied, just the actual tags for your operation.
84  * See struct rpi_firmware_property_tag_header for the per-tag
85  * structure.
86  */
87 int rpi_firmware_property_list(struct rpi_firmware *fw,
88                                void *data, size_t tag_size)
89 {
90         size_t size = tag_size + 12;
91         u32 *buf;
92         dma_addr_t bus_addr;
93         int ret;
94
95         /* Packets are processed a dword at a time. */
96         if (size & 3)
97                 return -EINVAL;
98
99         buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
100                                  GFP_ATOMIC);
101         if (!buf)
102                 return -ENOMEM;
103
104         /* The firmware will error out without parsing in this case. */
105         WARN_ON(size >= 1024 * 1024);
106
107         buf[0] = size;
108         buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
109         memcpy(&buf[2], data, tag_size);
110         buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
111         wmb();
112
113         ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
114
115         rmb();
116         memcpy(data, &buf[2], tag_size);
117         if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
118                 /*
119                  * The tag name here might not be the one causing the
120                  * error, if there were multiple tags in the request.
121                  * But single-tag is the most common, so go with it.
122                  */
123                 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
124                         buf[2], buf[1]);
125                 ret = -EINVAL;
126         }
127
128         dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
129
130         return ret;
131 }
132 EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
133
134 /**
135  * rpi_firmware_property - Submit single firmware property
136  * @fw:         Pointer to firmware structure from rpi_firmware_get().
137  * @tag:        One of enum_mbox_property_tag.
138  * @tag_data:   Tag data buffer.
139  * @buf_size:   Buffer size.
140  *
141  * Submits a single tag to the VPU firmware through the mailbox
142  * property interface.
143  *
144  * This is a convenience wrapper around
145  * rpi_firmware_property_list() to avoid some of the
146  * boilerplate in property calls.
147  */
148 int rpi_firmware_property(struct rpi_firmware *fw,
149                           u32 tag, void *tag_data, size_t buf_size)
150 {
151         struct rpi_firmware_property_tag_header *header;
152         int ret;
153
154         /* Some mailboxes can use over 1k bytes. Rather than checking
155          * size and using stack or kmalloc depending on requirements,
156          * just use kmalloc. Mailboxes don't get called enough to worry
157          * too much about the time taken in the allocation.
158          */
159         void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
160
161         if (!data)
162                 return -ENOMEM;
163
164         header = data;
165         header->tag = tag;
166         header->buf_size = buf_size;
167         header->req_resp_size = 0;
168         memcpy(data + sizeof(*header), tag_data, buf_size);
169
170         ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
171
172         memcpy(tag_data, data + sizeof(*header), buf_size);
173
174         kfree(data);
175
176         return ret;
177 }
178 EXPORT_SYMBOL_GPL(rpi_firmware_property);
179
180 static void
181 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
182 {
183         time64_t date_and_time;
184         u32 packet;
185         int ret = rpi_firmware_property(fw,
186                                         RPI_FIRMWARE_GET_FIRMWARE_REVISION,
187                                         &packet, sizeof(packet));
188
189         if (ret)
190                 return;
191
192         /* This is not compatible with y2038 */
193         date_and_time = packet;
194         dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);
195 }
196
197 static void
198 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
199 {
200         u32 packet;
201         int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
202                                         &packet, sizeof(packet));
203
204         if (ret)
205                 return;
206
207         rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
208                                                   -1, NULL, 0);
209 }
210
211 static void rpi_register_clk_driver(struct device *dev)
212 {
213         struct device_node *firmware;
214
215         /*
216          * Earlier DTs don't have a node for the firmware clocks but
217          * rely on us creating a platform device by hand. If we do
218          * have a node for the firmware clocks, just bail out here.
219          */
220         firmware = of_get_compatible_child(dev->of_node,
221                                            "raspberrypi,firmware-clocks");
222         if (firmware) {
223                 of_node_put(firmware);
224                 return;
225         }
226
227         rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
228                                                 -1, NULL, 0);
229 }
230
231 static void rpi_firmware_delete(struct kref *kref)
232 {
233         struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,
234                                                consumers);
235
236         mbox_free_channel(fw->chan);
237         kfree(fw);
238 }
239
240 void rpi_firmware_put(struct rpi_firmware *fw)
241 {
242         kref_put(&fw->consumers, rpi_firmware_delete);
243 }
244 EXPORT_SYMBOL_GPL(rpi_firmware_put);
245
246 static void devm_rpi_firmware_put(void *data)
247 {
248         struct rpi_firmware *fw = data;
249
250         rpi_firmware_put(fw);
251 }
252
253 static int rpi_firmware_probe(struct platform_device *pdev)
254 {
255         struct device *dev = &pdev->dev;
256         struct rpi_firmware *fw;
257
258         /*
259          * Memory will be freed by rpi_firmware_delete() once all users have
260          * released their firmware handles. Don't use devm_kzalloc() here.
261          */
262         fw = kzalloc(sizeof(*fw), GFP_KERNEL);
263         if (!fw)
264                 return -ENOMEM;
265
266         fw->cl.dev = dev;
267         fw->cl.rx_callback = response_callback;
268         fw->cl.tx_block = true;
269
270         fw->chan = mbox_request_channel(&fw->cl, 0);
271         if (IS_ERR(fw->chan)) {
272                 int ret = PTR_ERR(fw->chan);
273                 if (ret != -EPROBE_DEFER)
274                         dev_err(dev, "Failed to get mbox channel: %d\n", ret);
275                 return ret;
276         }
277
278         init_completion(&fw->c);
279         kref_init(&fw->consumers);
280
281         platform_set_drvdata(pdev, fw);
282
283         rpi_firmware_print_firmware_revision(fw);
284         rpi_register_hwmon_driver(dev, fw);
285         rpi_register_clk_driver(dev);
286
287         return 0;
288 }
289
290 static void rpi_firmware_shutdown(struct platform_device *pdev)
291 {
292         struct rpi_firmware *fw = platform_get_drvdata(pdev);
293
294         if (!fw)
295                 return;
296
297         rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
298 }
299
300 static int rpi_firmware_remove(struct platform_device *pdev)
301 {
302         struct rpi_firmware *fw = platform_get_drvdata(pdev);
303
304         platform_device_unregister(rpi_hwmon);
305         rpi_hwmon = NULL;
306         platform_device_unregister(rpi_clk);
307         rpi_clk = NULL;
308
309         rpi_firmware_put(fw);
310
311         return 0;
312 }
313
314 /**
315  * rpi_firmware_get - Get pointer to rpi_firmware structure.
316  * @firmware_node:    Pointer to the firmware Device Tree node.
317  *
318  * The reference to rpi_firmware has to be released with rpi_firmware_put().
319  *
320  * Returns NULL is the firmware device is not ready.
321  */
322 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
323 {
324         struct platform_device *pdev = of_find_device_by_node(firmware_node);
325         struct rpi_firmware *fw;
326
327         if (!pdev)
328                 return NULL;
329
330         fw = platform_get_drvdata(pdev);
331         if (!fw)
332                 goto err_put_device;
333
334         if (!kref_get_unless_zero(&fw->consumers))
335                 goto err_put_device;
336
337         put_device(&pdev->dev);
338
339         return fw;
340
341 err_put_device:
342         put_device(&pdev->dev);
343         return NULL;
344 }
345 EXPORT_SYMBOL_GPL(rpi_firmware_get);
346
347 /**
348  * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.
349  * @firmware_node:    Pointer to the firmware Device Tree node.
350  *
351  * Returns NULL is the firmware device is not ready.
352  */
353 struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,
354                                            struct device_node *firmware_node)
355 {
356         struct rpi_firmware *fw;
357
358         fw = rpi_firmware_get(firmware_node);
359         if (!fw)
360                 return NULL;
361
362         if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))
363                 return NULL;
364
365         return fw;
366 }
367 EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);
368
369 static const struct of_device_id rpi_firmware_of_match[] = {
370         { .compatible = "raspberrypi,bcm2835-firmware", },
371         {},
372 };
373 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
374
375 static struct platform_driver rpi_firmware_driver = {
376         .driver = {
377                 .name = "raspberrypi-firmware",
378                 .of_match_table = rpi_firmware_of_match,
379         },
380         .probe          = rpi_firmware_probe,
381         .shutdown       = rpi_firmware_shutdown,
382         .remove         = rpi_firmware_remove,
383 };
384 module_platform_driver(rpi_firmware_driver);
385
386 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
387 MODULE_DESCRIPTION("Raspberry Pi firmware driver");
388 MODULE_LICENSE("GPL v2");